Claude Opus 4.8
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MODEL ID
claude-opus-4-8Context
1M
Max output
128K
Latency
deep
Protocol
messages
Quick Start
Drop-in code to call this model with Felo API Platform compatible APIs. Start in the Playground when you want to test prompts before writing code.
Get your API key
Create a key from your Felo API Platform account and set it as an environment variable.
export FELO_API_KEY="YOUR_API_KEY"Make your first request
Use this model ID with the Felo API Platform endpoint. Optional request headers such as claude-opus-4-8 can help troubleshooting. X-Request-Id
This model is reasoning-capable. If your selected protocol and model route expose reasoning controls, preserve the returned reasoning metadata when continuing a conversation.
const response = await fetch("https://openapi.felo.ai/api/v1/chat/completions", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.FELO_API_KEY}`,
"Content-Type": "application/json",
},
body: JSON.stringify({
model: "claude-opus-4-8",
messages: [
{ role: "user", content: "How many r's are in the word strawberry?" }
],
}),
});
const data = await response.json();
console.log(data.choices[0].message.content);Using third-party SDKs
Use compatible SDKs by setting baseURL to baseURL https://openapi.felo.ai/api/v1. Use the Anthropic-compatible base URL for Claude-style clients. https://openapi.felo.ai/api.
Enable streaming
Add stream: true to receive responses as server-sent events.
curl -N https://openapi.felo.ai/api/v1/chat/completions -H "Authorization: Bearer $FELO_API_KEY" -H "Content-Type: application/json" -d '{
"model": "claude-opus-4-8",
"stream": true,
"messages": [
{"role": "user", "content": "Hello"}
]
}'Endpoint
Felo API Platform exposes compatible model-calling surfaces. Pick the surface your app or agent client already supports.
Chat Completions
Chat completion requests for compatible apps and agents.
POST
https://openapi.felo.ai/api/v1/chat/completionsResponses
Responses-compatible agent and workflow requests.
POST
https://openapi.felo.ai/api/v1/responsesMessages
Anthropic-compatible messages for Claude-style clients.
POST
https://openapi.felo.ai/api/v1/messagesParameters
modelstringclaude-opus-4-8Public model ID to call.messagesarrayrequiredConversation messages for Chat Completions.streambooleanfalseReturn server-sent events when true.temperaturenumber1Controls response variety when supported.max_tokensintegermodel defaultMaximum generated tokens.toolsarrayoptionalTool calling definitions following compatible schema.tool_choicestring or objectoptionalControls whether a tool should be called.response_formatobjectoptionalRequest structured output when supported.